The present invention relates to a method for automatically starting and stopping an open-end spinning machine of the type composed of a plurality of spinning units each including a spinning turbine, a breakup roller, a yarn extraction device and a winding apparatus.
The invention employs the basic concept that the yarn ends are to remain in the spinning turbines when the spinning machine is shut down and these ends are to be fed back into the spinning turbines upon restarting of the machine, this being achieved by a limited reverse operation of the yarn extraction devices and winding apparatuses.
When fiber rovings are spun into fine yarns, by a technique which does not employ the rings commonly associated with ring spinning, a strip of fibers consisting of staple fibers is fed via a feed roller to a rotating breakup roller and is there broken up into individual fibers. The individual fibers already broken out of the bundles of fibers are conducted by the subatmospheric pressure produced by the spinning turbine and by the flow conditions existing in the spinning chamber to the intake area of the spinning turbine, where they are conducted along the conical inlet portion of the spinning turbine into the fiber collection trough. From this point on, the fibers are then reinforced by twisting, are fed through the center of the spinning turbine as yarn, and are guided, by means of a pair of extraction cylinders, to winding apparatus.
During the usual shut-down of the spinning machine, the feed rollers, the spinning turbines, the breakup rollers, the extraction cylinders and the winding apparatuses are stopped. This results in a relatively rapid loss of the subatmospheric pressure required for the spinning process and thus causes all of the threads to break. During the usual restarting of the machine, it is then necessary to manually remove all broken threads. In this case each yarn end must be manually inserted into the yarn extraction tube and from there the subatmospheric pressure produced in the rotating spinning turbine sucks the yarn back into the fiber collection trough. There the individual fibers which were fed in the meantime to the input side of the spinning turbine by the feed roller and the breakup roller are then spun to the reintroduced yarn end, and the yarn which then forms is again continuously fed by the pair of extraction cylinders to the winding apparatus.
The reestablishment of spinning, by hand, described above insofar as concerns its significant steps is time-consuming, considerably reduces the output of the spinning machine and greatly increases personnel costs.